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From: Andi Kleen <ak@linux.intel.com>
To: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: paulmck@linux.vnet.ibm.com, peterz@infradead.org, akpm@linux-foundation.org,
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 Tim Chen <tim.c.chen@linux.intel.com>, linuxppc-dev@lists.ozlabs.org,
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Subject: Re: [PATCH v6 03/24] mm: Dont assume page-table invariance during
 faults
References: <1515777968-867-1-git-send-email-ldufour@linux.vnet.ibm.com>
 <1515777968-867-4-git-send-email-ldufour@linux.vnet.ibm.com>
Date: Tue, 16 Jan 2018 19:04:12 -0800
In-Reply-To: <1515777968-867-4-git-send-email-ldufour@linux.vnet.ibm.com>
 (Laurent Dufour's message of "Fri, 12 Jan 2018 18:25:47 +0100")
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Laurent Dufour <ldufour@linux.vnet.ibm.com> writes:

> From: Peter Zijlstra <peterz@infradead.org>
>
> One of the side effects of speculating on faults (without holding
> mmap_sem) is that we can race with free_pgtables() and therefore we
> cannot assume the page-tables will stick around.
>
> Remove the reliance on the pte pointer.

This needs a lot more explanation. So why is this code not needed with
SPF only?

-Andi